Thyroid Profile (T3,T4,TSH), Serum

The panel of Thyroid function tets typically includes tests for: Thyroid-stimulating hormone (TSH), Free thyroxine (Total or free T4), Total or free triiodothyronine (total or free T3). A thyroid panel is used to evaluate thyroid function and/or help diagnose hypothyroidism and hyperthyroidism due to various thyroid disorders. T4 and T3 are hormones produced by the thyroid gland which regulate the metabolic rate of tissues. Total and free T3 are assayed for the diagnosis of T3 thyrotoxicosis and hypothyroidism. Total T4 levels are measured in hyperthyroidism, primary, secondary and tertiary hypothyroidism, hypoproteinemia and severe non thyroidal illness. Free T4 levels are helpful in pregnancy, nephrotic syndrome etc., where total T4 levels are likely to be altered. TSH is secreted by the anterior pitutary which stimulates T3 and T4 formation and secretion. TSH measurement is done for screening of euthyroidism, screening of hypothyroidism in new born, diagnosis of hypo and hyperthyroidism and followup of T3 and T4 replacement therapy in hypothyroidism.

1. What are the conditions associated with hypo and hyperthyroidism?

The most common causes of are autoimmune-related thyroid disorders like graves disease which causes hyperthyroidism and Hashimoto thyroiditis which causes hypothyroidism. Thyroiditis, thyroid cancer, and excessive or deficient production of TSH can cause both hyper and hypothyroidism.

2. What is goiter?

Goiter is abnormal enlargement of the thyroid gland and may be associated with hypo, hyper or euthyroidism.

3. What are the additional blood tests that may be performed?

Thyroid auto - antibodies which help in differentiating different types of thyroiditis and identifying autoimmune thyroid conditions.

Calcitonin - Increased levels of calcitonin are seen in C-cell hyperplasia and medullary thyroid cancer.

Thyroglobulin - to monitor treatment of thyroid cancer.

4. How can I tell if my thyroid is working properly?

Both an underactive and overactive thyroid gland can cause symptoms. An enlarged thyroid gland either dissure or nodule, hoarseness of voice and symptoms like fatigue, depression, anxiety, weight loss or weight gain, temperature intolerances, hair loss, dryness of skin, or menstrual irregularities indicate a thyroid disorder.a thyroid disorder.